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High 7.5Published Sep 16, 2021

CVE-2021-41079Apache Tomcat DoS with unexpected TLS packet

Updated under an hour ago ()

Does this affect you?

It affects Apache Software Foundation Apache Tomcat and 3 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Apache Tomcat 8.5.0 to 8.5.63, 9.0.0-M1 to 9.0.43 and 10.0.0-M1 to 10.0.2 did not properly validate incoming TLS packets. When Tomcat was configured to use NIO+OpenSSL or NIO2+OpenSSL for TLS, a specially crafted packet could be used to trigger an infinite loop resulting in a denial of service.

CVSS
7.5 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-20
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
apache
NVD analysis
Modified
Record last updated
Oct 8, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
Apache Software Foundation Apache Tomcat
apache_software_foundation:apache_tomcat (from the name)
Apache Tomcat 8.5 8.5.0 to 8.5.63; Apache Tomcat 9 9.0.0-M1 to 9.0.43; Apache Tomcat 10 10.0.0-M1 to 10.0.2
CNA record
apache tomcat
apache:tomcat
from 8.5.0 before 8.5.64; from 9.0.0 before 9.0.44; from 10.0.0 through 10.0.2
NVD
debian debian_linux
debian:debian_linux
9.0; 10.0; 11.0
NVD
netapp management_services_for_element_software_and_netapp_hci
netapp:management_services_for_element_software_and_netapp_hci
all versions
NVD

References

  • x-refsource-misc
  • mailing-list, x-refsource-mlist
  • x-refsource-confirm
  • mailing-list, x-refsource-mlist
  • mailing-list, x-refsource-mlist
  • vendor-advisory, x-refsource-debian

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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